/Engine/Plugins/Editor/ObjectMixer/ObjectMixer/Source/ObjectMixer/Public/Views/List/Modes/ObjectMixerOutlinerMode.h
Select all descendants of a folder. Optionally select only immediate descendants.
virtual void SelectFoldersDescendants ( const [TArray](API\Runtime\Core\Containers\TArray)< [FFolderTreeItem](API\Editor\SceneOutliner\FFolderTreeItem) * > & FolderItems, bool bSelectImmediateChildrenOnly )